[vectorIntrinsics] RFR: Remove `byte[]` and `ByteBuffer` access methods.

[Paul Sandoz]

Removes `byte[]` and `ByteBuffer` vector access methods.

Fixes performance issue with the fallback implementation of `MemorySegment` accessors (the `ValueLayout` passed to the scalar accessors needs to be constant).

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Commit messages:
 - Remove scoped methods.
 - Fix execution error and typos
 - Impl and test chanages.

Changes: https://git.openjdk.java.net/panama-vector/pull/190/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=190&range=00
  Stats: 22199 lines in 88 files changed: 633 ins; 21234 del; 332 mod
  Patch: https://git.openjdk.java.net/panama-vector/pull/190.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-vector pull/190/head:pull/190

PR: https://git.openjdk.java.net/panama-vector/pull/190